Duct   |  
 Checks whether a duct size with the nominal diameter exists. 
 Namespace: Autodesk.Revit.DB.Mechanical
Assembly: RevitAPI (in RevitAPI.dll) Version: 25.0.0.0 (25.0.0.0)
Parameters
- nominalDiameter Double
 - Nominal diameter.
 
Return Value
BooleanTrue if a duct size with the nominal diameter exists.